// clippy1.rs
//
// The Clippy tool is a collection of lints to analyze your code so you can
// catch common mistakes and improve your Rust code.
//
// For these exercises the code will fail to compile when there are Clippy
// warnings. Check Clippy's suggestions from the output to solve the exercise.
//
// Execute `rustlings hint clippy1` or use the `hint` watch subcommand for a
// hint.


use std::f32::consts::PI;

//clippy 工具是一系列 lint 的集合，用于捕捉常见错误和改进 Rust 代码
fn main() {
    // let pi = 3.14f32;
    let pi = PI;
    let radius = 5.00f32;

    let area = pi * f32::powi(radius, 2);

    println!(
        "The area of a circle with radius {:.2} is {:.5}!",
        radius, area
    )
}
